Objectives: Renal impairment is an important complication following ileostomy formation, including both AKI and CKD. This systematic review analyses the incidence of renal impairment after ileostomy formation in patients undergoing resection for colorectal cancer. Methods: Observational studies on Pubmed, Embase and Cochrane Library that reported the incidence of renal impairment in patients who underwent ileostomy formation for rectal cancer surgery were included. Review articles, case reports, and studies with inadequate data, and non-English studies were excluded. Risk of bias for each included study was assessed using the ROBINS-E tool. Results: 10 studies were selected for review. All were retrospective cohort studies conducted between 2002 and 2020, with participant numbers ranging from 68 to 19,889. Each study analysed the incidence of renal impairment following ileostomy formation for colorectal cancer resections with follow up durations varying between 1 month up to 6 years. Heterogeneity was too high to conduct a meta-analysis. Discussion: Ileostomy formation is a risk factor for the development of both AKI and CKD. Limitations include the predominance of retrospective cohort studies rather than prospective studies. Additionally, significant heterogeneity meant a meta-analysis was inappropriate. This systematic review assesses the association between ileostomy formation and renal impairment in patients undergoing colorectal resections for colorectal cancer. It highlights the need for further research, in particular prospective cohort studies, to further assess the incidence and underlying mechanisms of this phenomenon and to identify potential interventions to mitigate the risk of renal impairment in these patients.